Mystery Case Files: MillionHeir is a puzzle adventure video game developed by Big Fish Games and Griptonite Games and published by Nintendo,[1] for the Nintendo DS handheld video game console. It was first released in North America, was later released in Australia, and then Europe. It is the second Mystery Case Files game to be made for a portable device. Although the game is part of the Mystery Case Files brand, it is not a part of the main computer game series.